CI: sync Docker Hub description via shared workflow (#6)

* CI: sync Docker Hub description via shared workflow

* CI: allow manual workflow dispatch

Author: f3l1x

.github/workflows/docker.yml

@@ -1,6 +1,8 @@
 name: "Docker"
 
 on:
+  workflow_dispatch:
+
   push:
     branches: ["master"]
 
@@ -27,4 +29,19 @@ jobs:
           - item: openjdk-mvn
           - item: openjdk8
 
-      fail-fast: false
+      fail-fast: false
+  docs:
+    name: "Docs"
+    needs: ["build"]
+    if: github.ref == 'refs/heads/master'
+    uses: dockette/.github/.github/workflows/dockerhub-description.yml@master
+    secrets: inherit
+    with:
+      image: "dockette/${{ matrix.item }}"
+    strategy:
+      matrix:
+        include:
+          - item: jdk8
+          - item: mvn
+          - item: openjdk-mvn
+          - item: openjdk8